More SMD goodness (hopefully!) *Even more boards added*

[stevie1556]

I suspect that via's being bad dates back to when fabbed PCBs were expensive, and fabbed PCBs with reliably plated through holes were even MORE spendy. (This is two or three decades ago!)

That definitely makes sense, especially as the technology has massively improved in that time.

I've just knocked up another layout from EP. It's the Leviathan and I've called it the Faux Paux. It was much easier then I anticipated to create, and I decided to split it into 2 sections, with the main signal section of the schematic and the power section on board one, and the PT2399 on board 2. The main reason is because I'm worried that the length of the board would be too long and not fit in the enclosure.

I can't decide if it's better to use those double sided sticky pads to attach the boards together, or to modify the boards and have double header pins holder them together. I'm looking forward to trying this one out, I'll get the boards ordered next week along with some others.

Anyway, here is the layout, it may change slightly if I use the double header pins.





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[stevie1556]

Yet another one, most likely the last one today. It's the 424 Demo Tape Fuzz, with the absolutely genius and inventive name of 828. Naming boards is definitely the hardest bit!

Already got this one for a 1590A, so thought a smaller version would be nice for my pedal board.



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[m-Kresol]

looking good! I was wondering where you get your parts from, especially tantalums, diodes and other actives. tantalums can be rather expensive, but they are way smaller than regular electrolytics..

[stevie1556]

I started using tantalums as I couldn't work out what the right footprints were in EagleCAD for the electrolytics. I get some tantalums from Rapid Electronics, but I mainly use Aliexpress. Most of my semi conductor stuff comes from there (ICs, Diodes, etc). Mouser has a lot of the parts, but they are more expensive and I point blank refuse to pay Mouser £12 for postage. FWIW, I've never received dodgy parts from Aliexpress, and the advantage is I've found some parts that aren't listed as SMD on the datasheets.

OK, this is definitely the last one for tonight, as I've got a long list of stuff that I need to get done. It's a DAM Meathead, I can't find a SMD version of the BC182L so I've had to use a TH one.



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[chuckbuick]

You're on fire, Stevie.  Same some SMD components for the rest of us 

[wgc]

I suspect that via's being bad dates back to when fabbed PCBs were expensive, and fabbed PCBs with reliably plated through holes were even MORE spendy. (This is two or three decades ago!)

This is pretty accurate I think. The other thing is in the early days of multilayer boards, a bad lamination could cause a via to split and then an open connection that couldn't easily be fixed. And then one would usually lead to more over time.

I use bias without shame but always feel like I did a better job if I can figure out a more direct path.

[stevie1556]

You're on fire, Stevie.  Same some SMD components for the rest of us 

Cheers buddy! I haven't sent the majority of the boards off yet so there is still some components about!

I've just had an email to say that Unicorn Slaying (Klon) has been shipped, so need to order the missing bits for that today.

This is pretty accurate I think. The other thing is in the early days of multilayer boards, a bad lamination could cause a via to split and then an open connection that couldn't easily be fixed. And then one would usually lead to more over time.

I use bias without shame but always feel like I did a better job if I can figure out a more direct path.

Totally makes sense. I remember back in the mid 90's my school tried having multilayer boards with vias made, over half didn't work and the rest failed within a short space of time. This was back when the school just bought their first heated etching tank for the electronics classes.

I really shouldn't have done this one today as I've got so much to do, but I've done another layout! It's for the Sweet Honey in the extra projects section, and I've called this one Honey Jar. Definitely won't have any time today to do anymore as I'm going to the running club this evening and the rest of the day I'm going to be pretty busy.

[stevie1556]

I've wanted to try out the Xotic EP Booster for quite some time now as I've always heard how good it is. It's just appeared in Etchers Paradise, so I've knocked up a quick SMD layout for it. It's going straight to the top of the pile of boards that I want made on payday.

It took about an hour for the schematic and layout, and creating a new part in Eagle (for the 2nd transistor). I've also got placement for a TH transistor for Q2 so I can have more transistors to experiment with).

More then likely the only layout I'm going to get today, gotta sort my car out as I hit a 4 foot crowbar a couple of weeks ago that trashed my tyre and alloy, and now the battery is flat. I used my car for 3 journeys on Sunday and each time is started ok, went to use it last night and the battery is flat. I'm hoping the crowbar didn't do any damage to the alternator or wiring. Got a battery charger hooked up to it so seeing if that does the trick.



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[stevie1556]

A friend of mind absolutely loves his Sweet Honey OD, but wants it in a 1590A to save space on his gigging board. I've knocked up a quick layout for it, going to send the boards off to the fab house tomorrow. Quite looking forward to building this one.



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[john_p_wi]

Wow, very prolific indeed.  I like your energy and drive, makes me want to miniaturize things lol.  I'm curious, it appears that you have done a copper pour on the top plane, but left the bottom unpoured.  Is there any reason for this?  In my day job of medical device instrumentation, the PCB guys work very hard at what we call "copper balance".  Besides the "ground plane" effect, as the boards become larger they try to balance the copper on the layers to avoid warping during processing or post processing environmental humidity / temperature changes which can be hell on smt boards with lead free solder.

Regarding reflow ovens, hot air etc, we don't use any in engineering for proto builds or debugging.  All hand placed down to 0402 size under a microscope using Metcal stations - of course the 200+ ball BGAs are usually placed at a board house and x rayed and inductors with bottom pads will get hot air.  To give you an idea of size and density, the last 6 layer board that I did a mechanical check on, approximately 4 in x 4 in, had over 2300 vias and took more than 5 minutes to load the EMN IDF 3D model in Pro-E! 

[stevie1556]

Cheers. I've got 2 basic layout plan rules for them now which definitely makes them quicker and easier to layout. There isn't any main reason why I use the copper pour on just the top layer, it's just the way I've always done it since I started learning Eagle 4-5 years ago. I can understand the concept of balanced copper pours, and never even considered it with mine. However, having said that, I've never had an issue with warping or failed boards out of all the SMD builds that I have done. I'll have a look into it though as it does sound interesting.

That's a hell of a lot of vias on that size board! I always assumed that 0402 and smaller parts were mainly done by pick and place machines, I don't think that I would want to hand place them. Whoever does that must have very very very steady hands!

I've just sent off the designs for Sweetness Driver (MP Sweet Honey OD), Swampy (Wampler Plexitone), 828 Fuzz (Demo Tape Fuzz) and Exotic Boosting (EP Booster). About to make a parts list to order the parts so i can build them up as soon as they arrive. I've just realised that I do actually have the diodes for Snitch, so as soon as the pots turn up I can get that verified (hopefully tomorrow). I tried getting away with using the 3mm pilot hole for the 3mm LED for the Green Envy pedal, but the LED doesn't fit snugly, so I need to drill the hole bigger for the holder then I can verify that one (hoping later today). Haven't done the rock it before you box it, so touch wood there won't be any issues.

[john_p_wi]

Again, as a guy in my 50's, I applaud your enthusiasm for smd conversion.  Keep us posted!

I'm finding that I am slowly converting to smd for a lot of amp build stuff, albeit a mixed bag of through hole and smt.

John

[EBRAddict]

When I put a via on top of a SMD pad I'm getting an "Overlap" error in Eagle using the DRU file from OSHPARK. How did you get around it?

[stevie1556]

John, thanks I would also love to see pictures of the amps in SMD/TH hybrids!

EBRA, I posted in your thread about the vias. I create the trace as normal with the vias, then just manually move them into the pads.

Just a little update on a few board designs. First is Blue Lagoon aka Zen drive. I've been up since 5am for work with 3 hours sleep and a 5 mile run when I got home, it's now 2050 so considering how tired I am it's quite an achievement that I've managed it. Gonna tidy the layout up a bit before I send them off to be made.



Next is the AM Radio aka LofoMofo. Love the pedal, it's great for the intro of I Believe In A Thing Called Love, and, err, that's about it. Got it in a 1590B so just a miniaturised version.



Goto an issue with Green Envy, I've built 2, the power LEDs don't seem to want to work, and the mix pot doesn't do anything. Gotta play around with them to see what's happening, or should I say what's not happening.

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[stevie1556]

Just a little update today, the Unicorn Slaying PCBs have just turned up, going to build up as much as I can if I get time today. Already got a paste stencil done for them. Got some bits ordered from Smallbear, but they probably won't be here for the better part of 2 weeks as they need to come across the pond. I'm also missing some of the resistors and caps, they have been ordered so it's just a waiting game now.



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